Passive RFID tags which operate in the UHF band (860 to 920 MHz) are known in the art. Known RFID tags comprise a RFID integrated circuit or a RFID tag module which is attached to an antenna, which can be a dipole, folded dipole, loop or patch antenna. In many situations it is desirable to use passive RFID tags for tagging objects or items such as products being sold in a supermarket, or animals or humans. The passive RFID tag can then be used, together with a tag reader, to detect the passage or presence of the tagged object, animal or human in a doorway, portal or similar. However, with currently permitted radio power levels under radio regulations in many jurisdictions the operating or reading range of standard tags is 70 cm or less, which limits the size of any doorway or portal. Furthermore, the physical orientation of the tag can limit the ability of a RFID reader to successfully read the tag.
In some aspects the present invention aims to provide a tagging technique which enables communication with a RFID tag over a reasonable distance whilst respecting other concerns such as privacy concerns and comfort. Other aims will be apparent from the description of preferred embodiments.